The present invention provides a process for the production of polyethylene, and more particularly, an efficient process for the production of polyethylene with wide distribution of molecular weight by employing a specific catalyst and by carrying out the polymerization in the presence of an alcohol in the reaction system.
In general, polyethylene utilized for producing molded articles such as bottles, cable sheathing and ultra-thin films must be able to withstand the molding conditions while in the plastic state and be easily molded into a predetermined shape. Therefore, it is necessary to employ a polyethylene having a wide molecular weight distribution.
The process described in Japanese Patent Kokai Koho 48584/1973 or 7488/1979 has been known as a process by which polyethylene having wide molecular weight distribution and excellent moldability and the like can be produced. In the process of No. 48584, one component of the catalyst is prepared by reacting an inorganic magnesium compound with an inorganic compound of a metal selected from the II to VIII group of the Periodic Table and a titanium halide in the presence of an electron donor. However, since the preparation of this catalyst is difficult and requires much effort, and because the catalyst obtained thereby is of variable quality, the process employing such catalyst lacks reproducibility. Furthermore, the process has a disadvantage in that the distribution range of molecular weight of the product polyethylene is not sufficiently wide. The process of No. 7488 is complicated and inefficient and requires a very expensive plant since the polymerization reaction is carried out in two stages.